Pyrrhotite (Fe7S8–Fe11S12) is an iron sulphide mineral found in igneous, metamorphic and sedimentary rocks. Naturally occurring pyrrhotite is a mixture of a ferrimagnetic monoclinc phase (Fe7S8) and antiferromagnetic hexagonal phases (Fe9S11 and Fe11S12). The range of environments that pyrrhotite forms in makes it an important mineral that is capable of carrying remanent magnetizations of thermal, chemical or detrital origin (e.g., Tuttle and Goldhaber, 1993; Menyeh and O’Reilly, 1998; Horng and Roberts, 2006). Pyrrhotite has also been identified as the main remanence carrier in some Martian meteorites (Rochette et al., 2001). The fact that pyrrhotite can carry a TRM means that it can potentially be used for Thellier-type paleointensity studies. During heating, however, pyrrhotite irreversibly oxidizes to magnetite and in the case of partial oxidation the coexistence of the two magnetic minerals can lead to self-reversing magnetization (Bina and Daly, 1994). Self-reversing magnetization in pyrrhotite may also be related to crystal twinning (Zapletal, 1992).
Pyrrhotite
Table of Contents
Physical Properties
Parameter
/Value
formula
28.679 (c0)
Magnetic Properties
Parameter
/Value
ordering
/Antiferromagnetic
(c-plane)
Common Occurrences
References
Further Reading
Can be removed if not needed.See Also
List of other relevant MagWiki pages.